Flotation process



. Patented Nov. 16, 1937 v i 2.099.120 FLOTATION raocnss James Emory Kirby and James Herbert-Werntz, Wilmington, DeL, assignors to E. I. du' Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 15, 1936,

- Serial N0. 105,676

Claims. 01. 209-166) a This invention relates to a method of separating the valuable mineral constituents of naturally occurring ores from the worthless or gangue materials. More particularly, it relates to an improved froth flotation method for separating and concentrating the desired mineral constituents the process will be understood by a consideration of the following*examples, it' being'understood' of natural ores. Still moreparticularly, it relates to the useof certain water-soluble salts of half esters of organic di-basic acidsin an improved froth flotation process especially applicable to the group of materials comprising the non-sulfide ores and coal.

This invention has as its object the development of an improved froth flotation method for the concentration of ores and'minerals, particularly those of the class comprising non-sulfldic ores and coal. A further object is the development of afroth flotation method for treating non-sulfide ores and coal having better selectivity than those heretofore known. Still another object is to provide a class of collecting and frothing agents for use in the flotation of non-sulfidic ores and coal, whose collecting strength, 'selectivlty, and frothing power can be controlled by a suitable choice of constituents used in preparing the flotation reagent. Another object is to provide a reagent for use in coal flotation which gives froths of better characteristics than those previously used. Further objects will appear hereinafter.

These objects are accomplished by utilizing as v a flotation reagent a water-soluble salt'of an organic di-carboxylic .acid having one carboxyl group esterif ied by an alcohol chosen from the class comprised of straight chain aliphatic primary alcohols having from 8 to 18 carbon atoms and alicyclic alcohols derived by carboxylic reduction from naphthenic acids and natural resin acids. I 3

In carrying out the process of this invention, a slurry of ground ore' or .coal and water (known as an ore or coal pulp) is treated with a small amount, usually from 0.05 pound to 2-3 pounds per ton of ground ore of a water-soluble half ester salt of the above specified type, either with or without the addition of other collecting, frothing or conditioning agents or oils, and subjected to agitation and aeration in one of the wellknown types of flotation cells. The'operation of that the invention is by no means limited to the conditions as outlined in the examples,

October 19, 1934. Two grams (0.0046 moi.) of

of the sodium salt of monoabietyl phthalate per Weight Size percent 30 Plus 40-mesh 0 Plus BO-mesh 56. 5 Plus -mesh 14. 0 Minus 100-mesh 29. 5 35 was finished. Another 5 cc. portion of the soadded and a second concentrate of poorer qual- 5 PATENT OFFICE I Example 1 A sample of monoabietyl phthalate COOH was prepared by reacting equ molecular proportions of abietyl alcohol and phthalic anhydride in the manner described in an application of- Barrett and Lazier Serial Number 749,070, filed the monabietyl phthalate was dissolved with the 5 aid of gentle warming in 20 cc. of one per cent sodium hydroxide solution. After diluting to 100 cc., the resulting solution contained 0.0210 g.

cubic centimeter of solution and a very slight ex- 20 cess of sodium hydroxide.

Fifty pounds of bituminous slack coal was ground through a pulverizer of the horizontal disc type until all was flner than 40-mesh. The ground coal was thoroughly mixed and carefully sampled. A sieve analysis showed the followingrange of particle sizes.

The crushed coal contained about 10 per cent of ash and 3 per cent of moisture.

' One thousand grams of the ground coal was slurried with water and transferred to a laboratory flotation cell of the subaeration type. After adding water to flll the cell to the pulp level, 30 cc. of the solution of sodium monoabietyl phthal- 45 ate was added. A froth loaded with coal particles quickly formed and flowed over the lip of the cell into a receiving vessel. The froth broke down rapidly allowing the coal particles to settle to the bottom of the receiving vessel. After 15 5 minutes at an agitator speed of 1100-1500 B. P. M., the collection of the first concentrate dium monoabietyl phthalate solution was then 'ity was obtained. During collection of this second concentrate the froth was again very satisfactory in volume and the floating coal was removed from the cell without any difliculty.

The products were filtered, dried, and analyzed for their ash content with results as shown in :fm'firstcnnceniratc, 1.30lbs.pu'ton.

ioracond concentrate, 0.22113. pcrton.

Example 2 A sample of an argillaceous limestone commonly' known as cement rock was obtained from the quarry of the Valley Forge Cement Company. West .Conshohoeken, Pennsylvania, 'Iherockwascrushedinasmalliaw crusher and then reduced to minus ill-mesh by means of a. Braun disc pulverizer. After thorough mixing, 1000 g. of the ground rock was further pul- I verized by grinding for '15 minutes in a one gallon pebble mill with one liter of water and 3 kg. of flint pebbles. The ground slurry, now about 85 per cent minus 200-mesh, was split into eight approximately equal portions by means of a sampie splitter.

A solution of'the sodium salt of -monoabietyl phthalate was prepared by dissolving 0.250 g. of

' monoabietyl phthalate in 46 cc. of 0.1 per cent sodium hydroxide solution and diluting to 100 cc. The resulting solution contained 0.00262 g. of sodium monoabietylphthalate per cubic centimeter.

One of'the portions of flnely ground ore slurry was washed into a small laboratory flotation cell of the mechanical agitation type described by Gates and Jaeobsen (Engineering and Mining Journal 119, 19, 7'11 (1925)). Ten cubic centimeters of the sodium monoabietyl phthalate solution was added and the agitator started. A froth well loaded with calcium carbonate parti- 'cles was quickly produced without addition of any other reagent. After running for four minutes, collection of the first concentrate was completed. An additional'5 cc. portion ofthe reagentsolution was added and a second concentrate was lifted into the froth. This second concentrate, also high in calcium carbonate, was collected in a separate container. After the run was completed the products were flitered, dried, weighed and analyzed for calcium carbonate,

the results being shown in the following table.

I 'Bight 0800 Product CaCO; med; gm m grams percent mm 40.2 90.2 .35-3 39.5 Second mmllm 39.0 95.8 37.3 40.7 42 2 43. 2 18. 2

Calcium mrbonate in feed, 75.6% (exiled). Toinl recovery, 80.2%. Rmgent: for first concentrate: 0.43 lb. per ton.

- for second concentrate 0.215 11:. per ton.

'Emmplc 3 A solution of the sodium salt of monododecyl phthalate was prepared by dissolving 0.250 g. of monododecyl phthalate in 34.5 cc. of 0.1 per cent sodium hydroxide solution and diluting to 100 The resulting solution contained 0.00279 g.

of sodium monododecyl phthalate and a small amount of free sodium hydroxide per cubic centimeter of solution. Another charge of ground cement rock similar to that used in the preceding example was placed in the small-flotation cell,

lowing results:

' Weight CaGO; Product Weght 5323; case, rwovery grams grams percent Concentrate 99.7 89.06 88.8 919 Tailings are 2146 as Calcium carbonateinfeed (calcd), 74.32%.

Reagent used, 0.65 lb. per-ton of feed.

A solution containing 0.0027 g. of sodium monon-octyl phthalate per cubic centimeter was prepared by dissolving 0.250 g. of mono-n-octyl phthalate in 45 cc. of 0.1 per cent sodimn hydroxide solution and diluting to 100 cc. Ten

cubic centimeters of this solution were used as the flotation agent in a test using a chargeof ground cement rock as in the two preceding examples. A satisfactory froth well loaded with calcium carbonate was produced. The flotation was com: plete in '7 minutes yielding results as summarized Calcium mrbonate in food (calcd), 74.39 per cent. Reagent med, 0.44 lb. per ton.

A higher recovery could readily have been produced by the use of a slightly greater amount of the flotation reagent.

With certain types of ores, particularly those which are earthy and poorly crystalline in nature, it is frequently beneficial to employ a collecting oil such as crude petroleum oil, a coal tar or wood tar distillate, kerosene, Diesel oil, or the like, along with a frothing agent to eifectthe flotation of a desired mineral. As an example of a flotation carried out in this manner, the concentration of an earthy manganese ore by use of gas oil and fish oil soap as carried out by the Cuban Mining 'Company at Cristo, Cuba, may be cited. Sometimes itis distinctly beneficial to emulsify the oil in water before adding it to the ore pulp in order to produce better contact between the desired mineral and the oil. The reagents forming the subject of the present invention may be used verymakes them extremely valuable reagents for use in the oilemulsion type of flotation process.

advantageously in ore flotation processes involving the use of emulsified oils, since they have been found to. possess strong emulsifying power. Their emulsifying power, combined with their frothing and collecting properties as already illustrated,

Two

- examples of the use of the new type of flotation was then prepared:

reagents in the oil emulsion flotation process follow.

' Example 5 One kilogram of minus 40-mesh manganese oxide ore from the Cuban Mining Company,

Cristo, Cuba, was ground for 30' minutes in a onegallon pebble mill with 3 kg. of flint pebbles, 1 liter of water and 5 g. of 40 per cent water glass.

The ground charge was diluted to avolume of 4 liters and then run through a laboratory elutriator to separate the sandy portions of the ore from the nearly colloidal slimes. The settlings, now largely free from slime, were slurried up with water and split into eight approximately equal samples for use in the small flotation cell described above.

An emulsion having the following composition Grams Sodium oleyl sulfate (27% paste) 0.066

Monododecyl phthalate -1 -1 0.300

Sodium hydroxide 0.300

'Panuco cmde oil 3.75 Water 50.00

The emulsion was diluted to a volume of cc. prior to use. Panuco crude oil is a Mexican petroleum oil. I v One of the deslimed ore charges was partially freed from water by siphoning off the supernatant water, and 38 cc. of the oil emulsion added. The mixture of ore slurry and emulsion was agitated for 90 seconds using a high speed drink mixer to afford thorough mixing and was then washed into the small flotation cell. As an aid to frothing, 2 drops (0.017 g.) of an oxygenated organic compound boiling from -160 C. prepared as described in the .U. S. Patent of Charles L. Burdick, No. 1,995,915, was added. A very satisfactory from carrying a heavy-load of black manganese minerals was formed. The froth broke down rapidly in the receiving vessel indicating that in large scale practice the flotation concentrate couldbe sent to'a thickener, for example, of the well-known Dorr type, to separate the mineral concentrate from the accompanying water. The products-from the flotation test were filtered and dried. The concentrate was nearly black in color indicating it to be high in manganese oxides while the tailings were grayish brown and sandy in appearance, obviously nearly free of manganese' The results maybe summarized as follows:

Frothing oil, B.-P. 150'-160 0.42

' Oxygenated frothing oil, B. P. 150-160 'It has been found that a very great variety of. water-soluble salts of half estersofcrganic'di-T. basic acids may be used in ore flotation with very Example 6 Y 7 I V An emulsion of the following composition was prepared:

Mono-octadecylphthalate grams; 0.100-

Sodium oleyl sulfate (27% paste) do {0.066

Sodium hydroxide do 0.150

Coal tar oiL; do 3.750

Water, to make a total of cc 150 The coal tar oil used is an oil obtained a; low.- temperature coking process. When ,distilled under atmospheric pressure, about 84 per cent of the oil distilled over in the temperature range of from to 300 C., the remainder .being a higher- 1 boiling residue. The oil contains cresols, xylenols,

and other phenolic, neutral, and basic ingredients.

,A flotation test similar to that describedin Example 5 was carried out using. 46.5 cc. of the above emulsion. As before, a small amount of. the oxygenated frothing oil boiling at 150160" C. was

added. Flotation proceeded satisfactorily giving;

aconcentrate rich in the blackmanganese minerals. The concentrate weighed 37.6 gror 57.5

per cent of the weight of the flotationfeed. The quantities of reagents used were as follows:

Mono-octadecyl phthalate Sodium oleyl sulfate (27% paste) Coal tar oil Sodium hydroxide satisfactory results if the alcohol, withI which one ofthe carboxyl groups of the diba siclacidis esterified, is chosen from the group comprising straight chain primary alcohols havingffrom '81 to 18 carbon atoms and the alicyclic alcohols.

The new class of flotation reagents may be rep resented by the following generalformula:

In this formula, M represents analkali metal such as sodium or potassium or" an ammonium group; R, a. divalent aliphatic, alicyclic or arc: matic radical; and R, alongstraight chain aliphatic radical having 8 to 18, carbon atoms in a saturated or unsaturated chain, or .an alicyclic radical formed in the carboxylic reduction; of a;

naphthenic acid or naturalresin acid. Eurlther,

without departing from thescope olthefpresent invention, the divalent radicaLjmay-poss ess various types of substituent groups such as-hy droxyl groups, alkyl groups, unsaturat'edflinkages, halogen groups, etc., orin a limiting case the radical, R. may be om e .alt efihflil ii the carboxyl groups joineddirectly'toeachother as in the case of oxalic acid.

The following are examples-of suitable dibasic 1 acids from which flotation agents coming under the scope, of the present invention may pared:

taric acid, phthalic acid, tere-phtljalic a id, h" hydrophthalic acid. I

Alcohols with which one of the carboxyl of acids, such as the above, may be esterifled are very numerous. The following partial listis illustrative of suitable alcohols which may be used in preparing the flotation reagents:

Pou ds per um i Oxalic acid, succinic acid wa acid; sebaeic" acid, maleic acid, fumaric acid, malic-a'cidj'tar-E ML-70 groups' n-octyl alcohol, n-decyl alcohol, n-dodecyl alcohol, n-tetradecyl alcohol, n-octadecyl alcohol,

, tioned half esters is described in more detail in Graves and Lawson Patents 1,993,736, 1,993,737, and 1,993,738; in Barrett and Lazier Patent 2,047,664, and in a co-pending application of Barrett and Lazier, Serial No. 749,070, flied October 19, 1934.

The half esters formed by reaction of alcohols and acids chosen from the above examples or similar half esters formed by any other suitable reaction are substantially insoluble in water, but,

since they retain one free carboxyl group, they may be converted to water-soluble salts by neutralization with suitable bases such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, etc.

It will be evident that aviary great number of difierentv half estersalts may be used in the operation of this invention without departing from the spirit thereof. as examplasof specific reagents which are useful in carrying out the process, the following may be mentioned.

Sodium monododecyl phthalate, sodium monoabietyl phthalate, sodium mono octadecyl phthalate, potassium monodihydroabietyl succinate, sodium mono-oleyl maleate, ammonium monododecyl phthalate, sodium mono-octyl succinate, sodium monodihydroabietyl phthalate.

By a. proper choice of alcohol, dibasic acid and salt-forming base, it is possible to exert a very large degree of control over the collecting, frothing, and selective properties of this new type of flotation reagents. Y I

The advantages of the invention derive largely from the'fact that according to the teachings of this invention it is possible to exercise-a very great degree'of control over the frothing and collecting power of the reagents by suitable changes in the molecular architecture. The reagents having very long carbon chains, say from 16 to 18 carbon atoms, are in general very powerful collecting agents and have great emulsifying power.-

1 in the long chain in general may be said to have superior frothing power while largely retaining the collecting and emulsifyin power of the higher members. When used in coal flotation, reagents of the class described in this invention give froths which are not only well loaded with coal particles but which also build up to a suflicient volume that their removal from the cell is greatly facilitated. Further, the froths break down rapidly in receiving vessels to a mixture of coal and water from which most of the water may be drained off readily. This is not true of the older coal flotation reagents such askerosene, cresylic acid and pine oil, which give very stable froths which are diflicult to dewater. A further advantage is that the new reagents frequently give satisfactory results when used in considerably smaller amounts than is possible with those previously known. a

In carrying out the processes of the present invention many modifications which may be made without departing from the spiritof the invention will be evident to those'versed in the art of ore flotation. Thus, for example, any of the wellknown types of flotation cells may be used. The ratio of solids to water in the ore pulp may vary addition to the pulp.

from about 1:1 to 1:6. The reagents may be used alone, since most of them have strong frothing power as well as collecting power, or they may be used in conjunction with previously known collecting, frothing, and conditioning agents. Since the reagents have the power to emulsify oils, they are very useful in theflotation process which employs oils emulsified in water prior to It is usually preferable to work in a neutral or alkaline pulp since the reagents are precipitated from solution byrnineral acids. 'Ihe salts employed may be added before. during or after or during the course of the flotation operation itself. Sometimes mixtures of two or more of the reagents of the presentinvention may be used together toadva e.

These reagents are particularly adapted for use in the flotation of'non-sulfide minerals of the type having an alkaline earth metal in the positive portion of the molecule, for example, calcite, fluorspar, barite, apatite, witherite, magnesite, dolomite, etc. They are not 'well adapted to the flotation of and the silicate minerals, and, for this reason, good-separation of the named alkaline earth minerals are possible. They are also useful in the flotation of carbonate minerals of the heavy metals, such as rho dochrosite, smithsonite and cerusslte. When used as a component of an oil emulsion, they are excellent reagents in the flotation of oxide ores of manganese. They have been found to be ex cellent reagents for use in coal flotation.

The above description and examples are to be ture therefrom which conforms to the spirit of the invention is intended to be included within the scope of the appended We claim:

1. In the froth flotation process of treating ores, the step which comprises utilizing as a flotation agent a water-soluble salt of an organic dicarboxylic acid having one carboxyl group esterified by an alcohol selected from the group consisting of long chain-primary aliphatic alcohols having from eight to eighteen carbon atoms and alicyclic alcohols formed in the carboxylic reduction of a naphthenic acid or a natural resin acid. 1

2. In the froth flotation process of treating non-sulfide ores and coal, the step which comprises utilizing as a flotation agent a watersoluble salt of an organic dicarboxylic acid having one carboxyl group esteriiied by an alcohol selected from the group consisting of long chain primary aliphatic alcohols having from eight to eighteen carbon atoms and alicyclic alcohols formed in the carboxylic reduction of a naphthenic acid or. a natural resin acid.

3. In the froth flotation process of treating nonsulfide ores and coal, the step which comprises utilizing as a flotation agent an alkali soluble salt of an aromatic dicarboxylic acid having one of the carboxyl groups. esterified with an alcohol chosen from the class consisting of straight chain aliphatic primary alcohols having from eight to eighteen carbon atoms and alicyclic alcohols formed in the carboxylic reduction of a naphthenic acid or a natural resin acid.

5. In the froth flotation process of treating non-sulfide ores and coal, the step which comprises utilizing as a flotation agent an alkalimetal salt, or an aromatic dicarboxylic acid having one of the carboxyl groups esterifled with an alcohol chosen from the class consisting of straight chain aliphatic primary alcohols having from eight to eighteen carbon atoms and alicyclic alcohols formedin the carboxylic reduction of a naphthenic acid or a natural resin acid.

6. In the froth flotation process of treating non-sulfide ores and coal, the step which comprises utilizing as a flotation agent an alkali metal salt of an ester of phthalic acid having one of the carboxyl groups esterifled with an alcohol chosen from the class consisting 01' straight chain aliphatic primary alcohols havalieyclic alcohols formed in the carboxylic reduction of a naphthenic acid or a natural resin primary alcohol having from eight to 7..In the froth flotation process oi treating non-sulfide ores and coal, the step which comprises utilizing sodium mono-abietyl phthalate as a flotation agent. a 1

8. In the froth flotation process or treating cement rock, the step which comprises utilizing as a flotation agent an alkali metal salt of an esteroi' phthalic acid having one of the carboxyl groups esterifled with a straight chain aliphatic primary alcohol having from eight to eighteen carbon atoms.

9. In the froth flotation process or treating manganese oxide ore, the step which comprises utilizing as a flotation agent an 'oil-in-water emulsion containing'an alkali metal salt of an ester of phthalic acid having one oi the carboxyl groups esterifled with a straight chain aliphatic ei hteen carbon atoms., 7

10. In the iroth flotation process of treating non-sulfide ores and coal, the step which-comprises utilizing sodium monododecyl phthalate as f a flotation agent. ing' from eight to'eighteen carbon atoms and' JAMES EMORY KIRBY. JAMES HERBERT mm. 

